The three-time champion at Roland Garros will next take on Australian Ash Barty in the second round.
However, she gave a stinging response to the doubters on Tuesday even if her win over the 70th-ranked Pliskova tested the American.
"Two years is a really long time but I have trained hard on clay and feel good", she said courtside afterwards.
The Russian appeared to be cruising at 6-1 3-1 ahead but Holland's Richel Hogenkamp suddenly had her on the ropes, taking the second set and racing 3-0 ahead in the decider.
If Pliskova does pull of an unlikely victory, it will be her first appearance in the second round of the French Open, having lost all three of her previous first-round matches. For the special occasion, she chose a unique outfit: a full length black bodysuit with a pink stripe.
After a 90-minute rain interruption at 5-5 in the first set Muguruza, the 2016 victor, blew 2009 champion Kuznetsova away in the tie break and went on to win 7-6 (7-0) 6-2.More news: Solo Launches to $148 Million Worldwide
Beginning his bid for a record-extending 11th championship at Roland Garros, Nadal needed to erase four set points to close things out Tuesday. Garcia, who celebrated her 28th major match win, will face Shuai Peng who beat 6-3 6-4 Aleksandra Krunic in her first WTA victory of the season.
Duckworth, who missed the French Open previous year because of foot surgery, has never won a match at the clay-court event in four appearances.
- Despite enormity of occasion, the 36-year-old, with her hair scraped back into severe-looking bob, the stadium is barely half-full as fans take a breather following Rafael Nadal's opening win.
Third-seeded Marin Cilic and James Duckworth played for a little more than one hour on Court Philippe Chatrier before they were sent back to the locker room by tournament officials.
Wimbledon champion Garbine Muguruza got the better of Svetlana Kuznetsova in a first-round meeting of two former champions.